This very technology has paved the way for setting global yield records. European experiences have reported annual harvests exceeding 100 kg/m2 for tomatoes and over 200 kg/m2 (442 lb/m2) for cucumbers.
Interplanting is a cutting-edge vegetable production technique that involves the simultaneous cultivation of mature and young plants. This innovative system allows for continuous harvesting throughout the year, as new seedlings are introduced alongside the mature plants.
What's particularly advantageous about interplanting is its adaptability: it can be integrated into existing greenhouses with some modifications. To successfully implement this system, additional growing gutters and drip lines are essential. Moreover, the use of artificial lighting is crucial to ensure optimal growth conditions for all plants, irrespective of their growth stage.
Exploring the concept of interplanting using cucumbers as an example
In conventional cultivation with artificial lighting, there is usually an approximate 4-week interval between harvesting the old plants and the commencement of fruiting in the new ones. However, in a supplemental lighting system, this downtime expands to 12 weeks without any harvest throughout the year.
Depending on the level of illumination and the greenhouse's location, this translates to approximately 265 tons (220 american tons) of cucumbers.
Interplanting is a widely used practice in both Finland and the Netherlands, with cucumbers and tomatoes being the favored crops for this method. Among the benefits of interplanting are significantly higher yields and year-round production. Notably, this approach allows producers to supply fresh produce to the market during the winter, when prices tend to be at their peak.
It's a little-known fact that Finnish greenhouse growers were the pioneers of the interplanting system, and the system's original design was as follows:
The greenhouse structure is designed with a 12.0-meter span and a minimum column height of 6.0 meters. Within a single span, there are ten hanging growing gutters, each 20 cm wide. These gutters accommodate slabs with plants, spaced to allow for the future planting of young plants. As the plants grow, the hanging gutters are gradually shifted, eventually forming five double gutters. Interlight lamps are suspended in the spaces between the gutters.
The underlying idea of this system is that as plants grow taller and foliage becomes denser, upper lighting struggles to penetrate through the thick foliage into the lower growth area. This results in cooler conditions below, where condensation can lead to plant diseases. Additionally, without the use of interlighting, there isn't sufficient light for young plants planted later in the growth cycle.
This classic interplanting method continues to be widely used in Scandinavian countries, where government support programs and favorable product prices facilitate the implementation of high-quality solutions without compromising on quality.
ADOPTION OF INTERPLANTING
IN THE NETHERLANDS AND OTHER COUNTRIES
In the Netherlands, as well as in our countries, producers are in pursuit of a balanced approach that considers the cost of equipment and the potential for productivity. Consequently, interplanting in both the Netherlands and our regions has evolved to adopt a somewhat different approach, where the greenhouse structure and internal equipment closely resemble traditional cultivation methods.
The greenhouse design typically includes an 8.0-meter span and columns with a minimum height of 6.0 meters. Within each span, there are usually five growing gutters.
There is one exception based on technical requirements, which involves the use of wider gutters (measuring 24 cm or 30 cm in width) and two separate drip lines operating from distinct mother tanks. The first growth cycle proceeds as usual. To synchronize harvest times, young plants are pre-planted, either 4 or 12 weeks before the commencement of fruiting, depending on the crop type. The process is fairly simple: new slabs are positioned in the gaps between the existing slabs, and drip emitters are inserted into the slots for each cube.
BE PREPARED FOR INVESMENTS
Farms prepared for investment utilize the interlight system, which results in a 15-20% increase in yield compared to using solely top lighting, with the exact improvement varying depending on the cultivated crop.
In many countries, it's common for complexes to be hesitant about investing in an extra lighting row. Instead, they resort to manually bending older plants to ensure light reaches the younger ones. To accomplish this, all plants on the trays are tied to one side, creating a dense row. As the young plants grow, they are secured to the other side. After this procedure, one row becomes densely planted, while the next remains spacious and well-illuminated. This alternating pattern continues: well-illuminated, densely planted, well-illuminated, and so forth.
Young and mature plants coexist until the mature ones stop bearing fruit, and the young ones start. This transition usually takes about 3-4 weeks for cucumbers and approximately 10 weeks for tomatoes. After removing the mature plants, the young ones are resecured on both sides of the tray.
If you're considering implementing interplanting, it's crucial to have the system designed by specialists who understand its principles and can tailor it to your specific needs. It's essential to set up the system in a way that ensures it functions correctly and delivers the expected results.